Abstract:

The present invention provides a sputtering apparatus and a method of thin
film formation, whereby a film having quality superior in uniformity even
for relatively large substrates can be obtained and the generation of
particles and nodules is suppressed. The sputtering apparatus of the
present invention includes: a vacuum vessel (9); a substrate holder (7)
for supporting a substrate (6); a cathode mechanism located opposite to
the substrate (6); and a second gas introduction mechanism for
introducing a gas into the vacuum vessel (9). The cathode mechanism has a
plurality of targets (1a) to (1c) arranged with a gap formed between each
other and a plurality of backing plates (2a) to (2c) arranged with a gap
formed between each other. A gap (14) between each of the targets is
smaller than a gap (15) between each of the backing plates. In addition,
the gap (14) overlaps with at least part of the gap (15). The second gas
introduction mechanism introduces a gas through the gap (15) and the gap
(14).

Claims:

1. A sputtering apparatus comprising:a vacuum vessel;a substrate holder
located inside said vacuum vessel to support a substrate;a plurality of
backing plates arranged opposite to said substrate holder to support a
plurality of targets; anda gas introduction mechanism for introducing a
gas into said vacuum vessel;wherein said plurality of backing plates are
arranged with a first gap formed between each other, andsaid gas
introduction mechanism introduces a gas through said first gap.

2. The sputtering apparatus according to claim 1, further comprising a
plurality of targets arranged on said plurality of backing plates with a
second gap formed between each other,wherein said plurality of targets
are arranged on said plurality of backing plates so that a second gap
between each of said targets is smaller than a first gap between each of
said backing plates and said second gap overlaps with at least part of
said first gap, andsaid gas introduction mechanism introduces a gas
through said first gap and said second gap.

3. The sputtering apparatus according to claim 1, further comprising:an
insulating plate which is located on a surface of said backing plates
opposite to a surface thereof for supporting said targets and has at
least one through-hole; anda support member which is located on a surface
of said insulating plate opposite to a surface thereof whereon said
backing plates are arranged, and in which a groove is formed;wherein said
insulating plate is located on a surface of said support member in which
said groove is formed; andsaid gas introduction mechanism introduces said
gas by way of said groove, said through-hole, and said first gap in this
order.

4. The sputtering apparatus according to claim 2, wherein said second gap
is within the range from 0.2 mm to 1.0 mm.

5. The sputtering apparatus according to claim 1, wherein a gas introduced
by said gas introduction mechanism into said vacuum vessel is a mixed gas
containing an inert gas and a reactive gas.

6. The sputtering apparatus according to claim 1, further comprising
another gas introduction mechanism provided separately from said gas
introduction mechanism and designed to introduce a gas from a position
separate from said backing plates.

7. The sputtering apparatus according to claim 6, wherein at least an
inert gas is introduced from said gas introduction mechanism and at least
a reactive gas is introduced from said separate gas introduction
mechanism.

8. The sputtering apparatus according to claim 7, wherein a mixed gas
containing said inert gas and said reactive gas is introduced from said
gas introduction mechanism and said separate gas introduction mechanism.

9. A method of thin film formation of forming a thin film on a substrate
using a sputtering apparatus according to claim 1, comprisinga step of
arranging said plurality of targets on said plurality of backing plates
with a gap formed between each other, wherein said plurality of targets
are arranged on said plurality of backing plates so that a second gap
between each of said targets is smaller than a first gap between each of
said backing plates, and said second gap overlaps with at least part of
said first gap.

10. The method of thin film formation according to claim 9, wherein said
introduced gas is a mixed gas containing an inert gas and a reactive gas.

11. The method of thin film formation according to claim 9, wherein the
sputtering apparatus further comprises another gas introduction mechanism
provided separately from said gas introduction mechanism and designed to
introduce a gas from a position separate from said gas introduction
mechanism,wherein at least an inert gas is introduced from said gas
introduction mechanism and at least a reactive gas is introduced from
said separate gas introduction mechanism.

12. The method of thin film formation according to claim 11, wherein a
mixed gas containing said inert gas and said reactive gas is introduced
from said gas introduction mechanism and said separate gas introduction
mechanism.

13. The method of thin film formation according to claim 12, wherein said
mixed gas is simultaneously introduced from said gas introduction
mechanism and said separate gas introduction mechanism.

14. A method of manufacturing a substrate by forming a thin film thereon
using a sputtering apparatus according to claim 1, comprising the steps
of:holding a substrate on said substrate holder; andsupplying a gas to
the substrate by introducing the gas through said first gap.

15. A method of manufacturing a substrate by forming a thin film thereon
using a sputtering apparatus according to claim 2, comprising the steps
of:holding a substrate on said substrate holder; andsupplying a gas to
the substrate by introducing the gas through said first gap and said
second gap.

16. The method of manufacturing a substrate according to claim 14, wherein
said introduced gas is a mixed gas containing an inert gas and a reactive
gas.

17. The method of manufacturing a substrate according to claim 16, wherein
the sputtering apparatus further comprises another gas introduction
mechanism provided separately from said gas introduction mechanism and
designed to introduce a gas from a position separate from said gas
introduction mechanism,wherein at least an inert gas is introduced from
said gas introduction mechanism and at least a reactive gas is introduced
from said separate gas introduction mechanism.

18. The method of manufacturing a substrate according to claim 17, wherein
a mixed gas containing said inert gas and said reactive gas is introduced
from said gas introduction mechanism and said separate gas introduction
mechanism.

19. The method of manufacturing a substrate according to claim 18, wherein
said mixed gas is simultaneously introduced from said gas introduction
mechanism and said separate gas introduction mechanism.

Description:

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001]This application is a continuation application of International
Application No. PCT/JP2008/067736, filed on Sep. 30, 2008, the entire
contents of which are incorporated by reference herein.

TECHNICAL FIELD

[0002]The present invention relates to a sputtering apparatus and a method
of thin film formation and, more particularly, to a sputtering apparatus
and a method of thin film formation whereby a film having quality
superior in uniformity is obtained and particle generation from a target
is suppressed.

BACKGROUND ART

[0003]In reactive sputtering in a sputtering apparatus, a reactive gas,
such as oxygen or nitrogen, is introduced along with an inert gas, such
as argon, in order to cause sputtering to take place within a vacuum
chamber. In such reactive sputtering, particles of a target material are
knocked out as the result of argon ions in generated plasma impinging on
the target material. The particles of the target material react with the
abovementioned reactive gas, and a film formed of a reactant generated by
the reaction deposits on a substrate. In addition, if the concentration
of the reactive gas is high, a surface of the target material reacts with
the reactive gas to form a compound layer. As the result of these
substances being sputtered, a reactant having a desired composition
deposits on the substrate.

[0004]In the case of a conventional sputtering apparatus, gas introduction
into a vacuum chamber is performed from near a wall of the vacuum
chamber. A gas concentration within the vacuum chamber is kept uniform
until plasma is generated. However, once the plasma is generated, a
reactive gas reacts with sputter atoms in the plasma and is thus
consumed. Therefore, the reactive gas is high in concentration around the
plasma but low in the central part thereof. In addition, as described
above, gas introduction is performed near a wall of the vacuum chamber.
Accordingly, even if the reactive gas is supplied in succession, the
reactive gas is first consumed by reaction outside the plasma. Thus, a
concentration gradient of the reactive gas may arise between the outside
and inside of the plasma. As a result, there may arise the problem that
the quality of a film deposited on a substrate differs between the
central part and the peripheral part thereof.

[0005]Hence, several proposals have been made in the past, in order to
solve the above-described problems.

[0006]According to Patent Document 1, there is disclosed a sputtering
apparatus in which a gas is also introduced from a plurality of small
holes provided in a target material or a plurality of small holes
provided in an interposition member interposed on a division surface of a
divided target, as well as from a conventional gas introduction port (gas
introduction port provided near a wall of the vacuum chamber).

[0008]However, although the method shown in Patent Document 1 is an
effective technique as the distribution of the reactive gas in the plasma
can be made uniform, the method has the below-described problems that
remain to be solved. First, in a method for introducing a gas by creating
small holes in the target material itself, which is one form disclosed in
Patent Document 1, the target material which is a consumable needs to be
machined, thus causing running costs to increase. In addition, small
holes also need to be created in a backing plate, thus requiring
significantly high precision when the target material having small holes
is bonded. Such problems as described above become increasingly serious,
as substrates and targets are increased in size.

[0009]Next, in a method for introducing a gas from a plurality of small
holes provided in the interposition member interposed on the division
surface of a divided target, which is another form disclosed in Patent
Document 1, a voltage is also applied to the interposition member at the
time of sputtering for reasons of apparatus configuration. Consequently,
not only the target material but also the interposition member is
sputtered and, therefore, substrates may be contaminated.

[0010]In addition, as substrates and targets are increased in size in a
parallel plate-type sputtering apparatus, backing plates also become
inevitably larger. On the other hand, it is difficult to make a large
backing plate as an integral component as a matter of manufacturing
methods or operations. Accordingly, a method is employed, for example, in
which a backing plate increased in size (also called a large-sized
backing plate) by putting together a plurality of members (also called
backing plate elements) is formed, and the large-sized backing plate is
attached to the apparatus. However, gaps among backing plate elements
serve as a source of particle generation and can be a cause for the
generation of nodules in the case of transparent conductive films, such
as an ITO film. That is, particles accumulate in the gaps among the
respective backing plates, and the accumulated particles pile up to form
nodules in the gaps. A progress in the generation of nodules causes such
problems as a drop in the rate of thin film formation and an increase in
the frequency of arc discharge. This in turn leads to shutting down the
apparatus to do the work of removing the nodules, thus degrading
manufacturing efficiency. In addition, the nodules may cause additional
particles to be generated, and the additional particles may, for example,
adhere to a film formed on a substrate, thus possibly causing the quality
of the film to degrade.

[0011]An object of the present invention is to solve the above-described
problems and provide a sputtering apparatus and a method of thin film
formation, whereby a film having quality superior in uniformity even for
relatively large substrates can be obtained and the generation of
particles and nodules is suppressed.

[0012]A first aspect of the present invention is a sputtering apparatus
including: a vacuum vessel; a substrate holder located inside the vacuum
vessel to support a substrate; a plurality of backing plates arranged
opposite to the substrate holder to support a plurality of targets; and a
gas introduction mechanism for introducing a gas into the vacuum vessel;
wherein the plurality of backing plates are arranged with a first gap
formed between each other, and the gas introduction mechanism introduces
a gas through the first gap.

[0013]A second aspect of the present invention is a method of thin film
formation of forming a thin film on a substrate using a sputtering
apparatus according to the first aspect, including a step of arranging
the plurality of targets on the plurality of backing plates with a gap
formed between each other, wherein the plurality of targets are arranged
on the plurality of backing plates so that a second gap between each of
the targets is smaller than a first gap between each of the backing
plates, and the second gap overlaps with at least part of the first gap.

[0014]According to the present invention, a gas distribution within plasma
is uniformized and it is reduced that members for supporting the targets
are sputtered. Consequently, it is possible to form a film having quality
superior in uniformity on a substrate, and reduce substrate
contamination.

[0015]In addition, as the result of introducing a gas from a gap between
each of a plurality of backing plates used due to an increase in the
sizes of substrates and targets, particles are less likely to accumulate
in the gap. Thus, it is possible to suppress the generation of particles
and nodules.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross-sectional side view illustrating a sputtering
apparatus in accordance with one embodiment of the present invention;

[0017]FIG. 2 is a front view of divided backing plates and targets in
accordance with one embodiment of the present invention;

[0018]FIG. 3 is a front view of a partition plate provided with an
insulating plate in accordance with one embodiment of the present
invention;

[0019]FIG. 4 is a cross-sectional front view of a partition plate in
accordance with one embodiment of the present invention; and

[0020]FIG. 5 is a front view illustrating a partition plate in accordance
with one embodiment of the present invention.

BEST NODES FOR CARRYING OUT THE INVENTION

[0021]Hereinafter, embodiments of the present invention will be described
in detail with reference to the accompanying drawings. Note that
components having the same functions are denoted by like reference
numerals in the drawings to be explained hereinafter and repetitive
descriptions will be omitted.

First Embodiment

[0022]Hereinafter, a sputtering apparatus in accordance with one
embodiment of the present invention will be described using FIGS. 1 to 5.

[0023]FIG. 1 is a cross-sectional side view illustrating a schematic
configuration of a sputtering apparatus in accordance with a first
embodiment of the present invention. This sputtering apparatus includes a
vacuum vessel 9, a substrate holder 7 provided inside the vacuum vessel 9
to support a substrate, and a cathode mechanism located opposite to the
substrate. This cathode mechanism has a backing plate 2 for supporting a
target 1. The target 1 is supported onto this backing plate 2.

[0024]In addition, a first gas introduction mechanism for introducing a
gas from a gas supply pipe 11A to the vacuum vessel 9 and a second gas
introduction mechanism for introducing a gas from a gas introduction pipe
11B to the vacuum vessel 9 are provided in the sputtering apparatus. The
first gas introduction mechanism is located separately from the backing
plate 2 of the vacuum vessel 9. The second gas introduction mechanism is
used to supply a gas from the backing plate.

[0025]The backing plate 2 is attached through an insulating plate 12 to a
partition plate 3 serving as a support member. The partition plate 3 is
attached, using unillustrated bolt members, to the vacuum vessel 9
forming a space in which sputtering is performed (hereinafter referred to
as the film-forming chamber). The partition plate 3 and the vacuum vessel
9 are vacuum-sealed using an O-ring 10. A magnet 8 is located on the
atmospheric side of the partition plate 3.

[0026]Note that in the present embodiment, the partition plate 3 and the
vacuum vessel 9 are coupled with each other using the O-ring 10. However,
without limitation to this, the partition plate 3 and the vacuum vessel 9
may be coupled with each other using, for example, an adhesive agent or
bolts and nuts. Thus, any members or materials may be used as long as the
partition plate 3 and the vacuum vessel 9 can be coupled with each other.

[0027]FIG. 2 is a front view illustrating a condition in which the target
1 is attached to the backing plate 2.

[0028]As illustrated in FIG. 2, the target 1 has three target members
(sub-targets), targets 1a, 1b and 1c, arranged at predetermined
intervals. In the present specification, a group of the targets 1a, 1b
and 1c is referred to as the target 1. In addition, the backing plate 2
has three backing plates (sub-backing plates), backing plates 2a, 2b and
2c, arranged at predetermined intervals. In the present specification, a
group of the backing plates 2a, 2b and 2c is referred to as the backing
plate 2. The targets 1a to 1c may be formed by dividing one target or may
be separate targets. Likewise, the backing plates 2a to 2c may be formed
by dividing one backing plate or may be separate backing plates. Use of
separate backing plates is preferred, however, since it is possible to
easily cope with sputtering to large-sized substrates.

[0029]FIG. 4 is a cross-sectional front view illustrating a condition in
which the target 1 and the backing plate 2 are provided on the partition
plate 3. The backing plate 2 and the target 1 are attached to the
partition plate 3 through an insulating plate 12. Gas introduction
grooves 5 are provided in the partition plate 3. The gas introduction
grooves 5 are formed as trenches on the insulating plate 12 side of the
partition plate 3. Part of each gas introduction groove 5 is connected to
the gas supply pipe 11B for introducing a gas into the vacuum vessel 9.

[0031]Note that in the present embodiment, the partition plate 3 is
provided as a member separate from the vacuum vessel 9 and is coupled
with the vacuum vessel 9 using the O-ring 10 or the like serving as
connection means. However, without limitation to this, the partition
plate 3 and the vacuum vessel 9 may be integrated with each other. That
is, a predetermined wall of the vacuum vessel 9 may be allowed to
function as the partition plate 3. In this case, a mechanism of
connection between each gas introduction groove 5 and the gas
introduction pipe 11B may be formed on the predetermined wall of the
vacuum vessel 9.

[0032]FIG. 3 is a front view illustrating a condition in which the
insulating plate 12 is attached to the partition plate 3. A plurality of
holes (through-holes) 13 are provided in the insulating plate 12. The
holes 13 of the insulating plate 12 are provided in positions
communicated with the gas introduction grooves 5 (dashed lines) on the
back side of the insulating plate. That is, the holes 13 are positioned
so as to let a gas supplied to the gas introduction grooves 5 pass
through.

[0033]Note that in the present embodiment, a gas is supplied from gas
introduction pipe 11B side to the film-forming chamber side through the
gas introduction grooves 5 and the holes 13, separately from the gas
introduction pipe 11A located near a wall of the vacuum vessel 9. That
is, a gas is supplied from the holes 13 formed in the predetermined
positions of a cathode mechanism within a region where plasma is
generated. With a gas supplied from these holes 13 into the film-forming
chamber, it is possible to reduce the concentration gradient of a gas,
such as a reactive gas. Accordingly, arranging the plurality of holes 13
along the longitudinal direction of each gas introduction groove 5, as
illustrated in FIG. 3, is preferred since it is possible to uniformly
supply a gas into the region where plasma is generated and further
uniformize the abovementioned concentration gradient. Even if only one
hole 13 is formed, however, it is still possible to supply a gas into
generated plasma. Thus, it is possible to reduce the abovementioned
concentration gradient by a corresponding amount. As described above, in
the present embodiment, it is possible to attain the above-described
advantage by forming at least one hole 13 so that the gas introduction
grooves 5 and the film-forming chamber are communicated with each other.

[0034]The respective backing plates 2a to 2c composing the backing plate 2
are arranged on the insulating plate 12 with a gap formed between each
other. At this time, the respective backing plates 2a to 2c are arranged
so as not to block all of the holes 13 formed in the insulating plate 2.
That is, the backing plates 2a to 2c are positioned so that a gap 15
between each of the backing plates 2a to 2c overlaps with some of the
holes 13. In addition, a gap 14 between each of the targets 1a to 1c
overlaps at least part of the gap 15 since a gas passing through the gap
15 needs to be introduced into the film-forming chamber. By forming the
gap 14 and the gap 15 in this way, it is possible to supply a gas
introduced from each gas introduction groove 5 into the film-forming
chamber.

[0035]In addition, the respective targets 1a to 1c composing the target 1
are arranged on the backing plate 2 with a gap serving as a gas ejection
port 4 formed between each other. The target 1 is provided on the backing
plate 2 so that the gap 14 between targets is smaller than the gap 15
between backing plates. By making the gap 14 smaller than the gap 15 in
this way, it is possible to let the targets 1a to 1c function as masks
against plasma, thereby preventing the backing plates 2a to 2c from being
exposed to plasma. Accordingly, it is possible to prevent the backing
plates from being sputtered and reduce substrate contamination.

[0036]The gap 14 between targets is preferably 0.2 mm or larger but not
larger than 1.0 mm. By setting this gap to 1.0 mm or smaller, it is
possible to prevent sputter particles from bypassing through the gap. In
addition, by setting the gap to 0.2 mm or larger, it is possible to
prevent gas ejection out of the holes 13 from being blocked at gas flow
rates in a commonly-used range.

[0037]Note that in the present embodiment, the backing plate 2 is a group
of the vertically triparted backing plates 2a, 2b and 2c (sub-backing
plates) and the target 1 is a group of the targets 1a, 1b and 1c
(sub-targets), as illustrated in FIG. 2. However, the number and the size
of the sub-backing plates and the sub-targets may changed arbitrarily.

[0038]In addition, in the above-described embodiment, holes serving as gas
supply ports are provided in the insulating plate. Alternatively, a
plate-like body may be used without limitation to the insulating plate.

[0039]The gas introduction mechanism 5 is connected to the gas
introduction pipe 11B on the atmospheric side by way of the gas
introduction grooves provided in the partition plate 3. Accordingly, it
is possible to reduce a distance between the target 1 and the magnet 8
even in cases where a gas introduction path is provided between the
target 1 and the magnet 8, so as to supply a gas into generated plasma.
Thus, it is possible to increase a magnetic field strength on a surface
of the target 1. Here, the magnet 8 is preferably able to swing in
parallel and laterally with respect to the target 1, in order to enhance
the utilization efficiency of the target 1.

[0040]Thin film formation in a reactive sputtering apparatus having the
above-described configuration is carried out by following steps described
hereinafter. First, the targets 1a to 1c are located on the backing
plates 2a to 2c arranged at predetermined intervals, as illustrated in
FIGS. 2 and 4. That is, the targets 1a to 1c are disposed on the backing
plates 2a to 2c so that a gap between each of the targets 1a to 1c is
smaller than a gap between each of the backing plates 2a to 2c, and that
the gap between each of the targets 1a to 1c overlaps with at least part
of the gap between each of the backing plates 2a to 2c.

[0041]Next, an inert gas, such as argon, and a reactive gas, such as
nitrogen or oxygen, are previously flow-controlled using an MFC (mass
flow controller) or the like, so as to have a predetermined pressure, and
then supplied as a mixed gas from the gas introduction pipes 11A and 11B.
Introduction of the above-described mixed gas is performed simultaneously
from a first gas introduction mechanism whereby a gas is introduced
directly into the vacuum vessel, and from a second gas introduction
mechanism whereby a gas is introduced, by way of the gas introduction
grooves 5 inside the partition plate 3, from the gas ejection port 4
through the gaps included in the backing plate 2 and the target 1 into
the vacuum vessel 9.

[0042]Next, electric power is applied to the target 1 using a DC power
supply or the like to perform reactive sputtering, thereby forming a film
on a substrate 6 opposite to the target 1. Note that the electric power
is supplied from the DC power supply to the target 1, by way of the
partition plate 3, using a power supply path penetrating through the
insulating plate.

[0043]Note that in the above-described embodiment, the first gas
introduction mechanism and the second gas introduction mechanism are
provided in the vacuum vessel, and the mixed gas containing an inert gas
and a reactive gas is supplied from the respective gas introduction
mechanisms. It is not essential, however, to introduce the mixed gas from
both the first gas introduction mechanism and the second gas introduction
mechanism. The essence of the present invention is to uniformize the
concentration gradient of the reactive gas in a region where plasma is
generated. In the present invention, it is possible to reduce the
concentration gradient of the reactive gas if the reactive gas is
supplied from the second gas introduction mechanism. In addition, since
at least a reactive gas is supplied from the second gas introduction
mechanism, only an inert gas for sputtering a target may be introduced
from the first gas introduction mechanism. That is, at least a reactive
gas may be supplied from the second gas introduction mechanism and at
least an inert gas may be supplied from the first gas introduction
mechanism.

[0044]As described above, in the present embodiment, the plurality of
backing plates 2a to 2c and the plurality of targets 1a to 1c are
arranged with gaps provided thereamong, the gas introduction grooves 5
connected to the gas introduction pipe 11B are formed along the
longitudinal direction of these gaps, and the gaps 14 and 15 are formed
so as to let a gas supplied from the gas introduction grooves 5 pass
through. Accordingly, a reactive gas can be supplied from a region within
a target to a region between a cathode mechanism and the substrate 6.
Thus, it is possible to reduce the concentration gradient of the reactive
gas in a region of generated plasma. Consequently, it is possible to
uniformize the quality of a film to be formed on the substrate.

[0045]Conventionally, a plurality of backing plates have been arranged in
order to increase the size of substrates or targets. Accordingly, there
have been cases in which particles accumulate in gaps among the backing
plates and serve as a source of particle generation. In the present
embodiment, however, gaps among backing plates are allowed to function as
part of a gas introduction path. Accordingly, accumulation of particles
in the abovementioned gaps decreases, thereby making it possible to
suppress the generation of nodules and particles.

[0046]Furthermore, in the present embodiment, a plurality of backing
plates and a plurality of targets are used, and part of a gas
introduction path is formed by utilizing gaps formed when these backing
plates and targets are arranged. Accordingly, it is possible to supply a
gas to a region between the cathode mechanism and the substrate without
the need for carrying out machining to create holes in targets and
backing plates or provide an interposition member as in Patent Document
1. Consequently, it is possible to carry out reactive sputtering at
reduced costs. In addition, by arranging the backing plates and the
targets as described above without the need for applying the
abovementioned machining, it is possible to form a gas introduction path.
Accordingly, it is possible to use existing backing plates and targets
without the need for machining, and easily increase the sizes of
substrates and targets.

Second Embodiment

[0047]In the first embodiment, an explanation has been made of a form
which includes both the first gas introduction mechanism and the second
gas introduction mechanism. In the present embodiment, an explanation
will be made of a form in which the first gas introduction mechanism is
not provided.

[0048]When a mixed gas containing an inert gas and a reactive gas is
introduced from the second gas introduction mechanism, both the inert gas
and the reactive gas are introduced between the cathode mechanism inside
the vacuum vessel 9 and the substrate 6. In addition, the second gas
introduction mechanism is designed to supply a gas, so as to reduce the
concentration gradient of the reactive gas in a region between the
cathode mechanism and the substrate 6, which is a region where plasma is
generated. Accordingly, the inert gas and the reactive gas are supplied
to the region where plasma is generated, without the need for providing
the first gas introduction mechanism including the gas introduction pipe
11A. In addition, it is possible to uniformize the concentration gradient
of the reactive gas.

[0049]As described above, in the present embodiment, when the mixed gas is
supplied from the second gas introduction mechanism, if the first gas
introduction mechanism is not provided in the vacuum, it is possible to
realize the same advantage as that of the first embodiment, if.

[0050]Having thus described the preferred modes and embodiments of the
present application with reference to the accompanying drawings, the
present invention is not limited to these modes and embodiments, but may
be modified into various other forms within the technical scope
understood from the description of the scope of the appended claims.